Various UV imprint lithography methods using UV-curable resin as photo-curable resin are available. In one these methods, ink-jetting, for example, is performed, discretely applying the resist material into spaces made in the surface of a substrate. This method is advantageous in that the resist is applied at designated positions in a required amount in accordance with the arrangement of patterns on a template, whereby the resist film remaining between the template and the substrate can have is so-called residual layer thickness (RLT) that is uniform for the patterns. The technique of imparting uniform thickness to the resist film of RLT is useful in increasing the dimensional precision of the patterns processed.
In order to form fine patterns, the resist pattern must have a small height (i.e., small thickness). Otherwise, the resist pattern may be broken when the template is separated from resist, or the resist material may not fill the spaces on the template. If the resist pattern becomes thin, the RLT must be reduced to compensate for the inadequate thickness of the resist film, i.e., process mask used in processing the film formed on the substrate.
To form a resist pattern of a small height and to reduce the RLT, however, the amount of the resist applied in any specific region must be decreased. The total amount of resist discretely applied in that region, discretely, or in the form of droplets, should therefore be decreased. In view of the pattern dimension precision due to the variation of the RLT, it is not desirable to place the resist droplets merely sparsely. It is indeed desired that the resist droplets should be reduced in volume. For the size of resist droplets to apply onto the substrate, however, the lower limit exists because of the restriction imposed on the ink-jet head.
If the main component of the resist material is a volatile one, as in the case of UV-curable resin of radical polymerization type, the resist applied from the ink-jet nozzle can indeed be reduced in volume. However, the main component evaporates in different amounts in the respective unit regions at which the imprinting is performed once by using the template.